Variable pitch pulley



Sept. 30, 1952 c. H. MINER 2,612,055

7 VARIABLE PITCH PULL-BY Filed July 26, 1950 IN V EI V TOR. CWARLL'S MINE BY ATTORNEYS Patented Sept. 30, 1952 UNITED IsrArEs VARIABLE rrrcn Putter Charles Hughl /iinen llenivez'pcole. Application July 28,1950, Serial No. 175,931 4 Claims. (Cl. fi s-230.17)

This invention relates to V-belt power transmission systems and more particularly tovariable pitch pulleys employed therewith.

In certain V-belt power transmission systems, particularly those in which the drive and driven pulleys are disposed on fixed centerdis tances, it is common practice to provide a drive pulley which increases in effective pitch diameter f in response to increase in its speed and to pros vide a'driven pulley having relatively movable side flanges which are spring urged in a direction su 1 that they tend to provide a maximum effective pitch diameter. When the drive pulley is rotating at apredetermined low speed it is at minimum eflective pitch diameter and the driven pulley is at maximum eifective'pitch diameter. speed it approaches maximum effective pitch di .ameter and the driven pulley approaches vrninimum effective pitch diameter, but as the latter As the drive pulley increases in does so the force of the flanges on the V-belt increases due to increase in the urge of the resilient actuating means forming a part ofthe driven pulley.

One of the objects of the invention is to pro;

vide a transmission system of "the type. above referred. to in which the driven pulley isprovided with centrifugally responsive fmeans'ffor assisting in moving it to smaller effectivefpitch diameter with increase in speed thereof and to obviate unnecessary and objectionable side pres A further object is to provide a driven pulley which minimizes certain wear on its moving parts which latter causes improper relative positioning of its belt contacting flanges.

Still further objects, advantages; and salient features will become more apparent from a consideration of the description to follow, the appended claims, and the accompanying drawing, in which: I

Figure 1 is a side elevation and longitudinal section through a'V-pulley, the section being taken on line l-l, Figure 3; V

Figure 2 is asection taken on line 2*2, Figure 1;

Figure 3 is a section taken, on line 3-3, Figure 1;

" joins the horizontal channels and aids in retain 1 ing them in proper alignment, this member bethe channels are ure3;and I Y Figures 5 and 5A diagrammatically illustrate a Vf-belt power transmission system utilizing the subject of-the inventionjthe relative position ing of the parts being at two difierent speeds of operation.

Referring in detail to the drawing, thepullefy v it comprises" an elongated hub it having a -plurality of integral splines l2 spaced peripherally and extending longitudinally thereon One side flange l3 of the pulley is connected to a sle eve i having a smooth cylindrical bore lli jth'e'rein, this sleeve being disposed concentricwiththe pulley axis l6 and rigidly secured to one end jof the sleeve by a connecting h v I a A movable side flange I8 isrigidl sec a sleeve iii, the outer surface of the-latter telescopically. fitting bore so that it is free to slide but is snugand without playthereini The inner surface is splined to snugly fit-splines l2. A

packing such as O-ring disposed in'an annular-groove in sleeve l4 prevents'loss of lubricant which is contained in space 2! and also prevents foreign matter from entering bore I-5. A grease gun fitting ZZis threadedly connected to sleeve it for filling space 2| with grease or other' suitable lubricant.

'A cylindrical tubular housing 23 is integrally secured at one end thereof to theperipheral edge of flange I8, its other end being substantially closed by a plate 24 secured to the housing byfa plurality of screws 25. Plate 24 is providedwith a cup-shaped portion 26 terminating with an annular flange 21 a'gainst 'which' abuts one end of a compression coil spring 28', the other end of a I the spring abutting a cup washer 2.9,retained on hub H by a snap ring 30 which removably engages a groove in the hub. As will be apparent, spring 28 urges flange 19 toward flange l3 and tends to move V-belt 3llradially outwardfto a position wherein the pulley has a maximum effec: tive pitch diameter. j

A centrifugal device 32. opposes the force of the spring just described, this device comprising a hub 33 having a cylindrical bore 34 which fits hub H andis secured to the latter by. a set A plurality of spoke-like members 35 are integrally formed on thehub, these mem screw 35.

here each having a substantially radial circular channel 3! which joins a circular channel 31a, the latter being parallel with axis 16. A'plurality of metal balls 38 are disposed in the channels, and form a train adapted to exert a force against pins 39 fixedly secured to plate 24. A ring 40;

formed integral with the centrifugal device;-

ing optional and not required if otherwise sufficiently rigid.

* OFFICE:

Figure l'isa section takenonline l-JQQ my copending application, Serial No. 81,909, now

Patent Number 2,553,505, of which the present application forms a continuation-impart. In Figure the drive pulley 46, just referred to, is operating at low speed and has a relatively small effective pitch diameter, driven pulley it. having a maximum effective pitch diameter. .As drive pulley 46 increases in angular velocity its side flanges finally assume a position wherein the pulley is at maximum effective pitch diameter 4 tion, the beating or brinelling action breaking down any lubricant film on the splines and resulting in rapid wear. Prior art pulleys have been subject to the foregoing disadvantage since .no adequate provision has been made to efiectively lubricate the splines. Also, where it has been possible to apply lubricant thereto no provision has been made to prevent excessive lubricant from flying outward onto the belt, this causing rapid belt deterioration and/or belt slippage. This invention obviates these disadvantages sincehub I9,.sleeve I4, and seal provide a lubricant reservoir 2| which maintains the spline properly lubricated at all times. The snug telescopic fit of hub 19 in sleeve l4 also steadies flange .18 against .forces tending to wobble it which .inv turn prevents a break-down oi the lubricant film on .the splines.

and the driven pulley I0. is at minimum eiiective pitch diameter, the speed ratio between. the

pulleys, of course, changing between these limits.

If the centrifugal device 32 were not provided, the full urge of spring 28 in its compressed-state would be applied to side flange 1 8 and to the belt 3 l tending to urge it outwardly thus unnecessarily tensioning thebel-t. Since the power transmitted by a belt is a function of the difference in tension between the two runs thereof,- it is desirable .to tension the so-called slack side no more than is necessary topullthe-load to thus minimize the tension inthe tension. or load. carrying run of the belt. The centrifugal deviceoi this invention is adapted to attain this result byreducing the urn necessary tension in. the tension. or driving run Having described .the invention, what I claim asv new is:

1. Avariableratio pulley. comprising, a pair of axially aligned membersv having juxtaposed faces of a shape to engage. the sides of a V-belt therebetween, the width of the races in a radial direction being substantially in excess of the thickness of, the belt, means connecting the members. together in. a manner such that they rotate, in unison, .butare relatively movable axially, resilientmeans urging the members toward each other, means rotatable with the pulley responsive to centrifugal force. opposing a portion of the urgeoithe. resilient means, thelast named means having a fixed mass, andcomprising a channel extending outwardly from. the axis of. the pulley,

' joined at. its. outer. end to a channel extending 7 parallel. with the, axis, and a plurality of conoi the belt by opposing the urge or spring 28 as this spring urge. tends to, increase with increase in angular velocity of the driven member.

It will be observed that when one of the balls 38 enters channel 31a it no longer applies any centrifugal controlling force to a pin 39 and the effective centrifugal force is only that. applied by the balls remaining in radial channel 31. By the Ch ice of. the number of. balls this controllin force can be limited. For example, if all balls are in channel 3-! at a predetermined. speed, except one, this latter ball, or only a portion of its eiiective weight, is utilized to apply a. controlling force, to the ball train. Further, the controlling force at any predetermined speed, may be. varied by va ying the number of balls. and their relative weights, Some of the balls, for. example, may be of steel or other relatively heavy material and others oi aluminum, or the, like, of relatively light material. The. controlling iorce will also vary depending on the. position of the. balls in the train. If one or more balls oflightmaterial are disposed inchannels. 38 at a, particular speed of ro ation. and. heavy balls are disposed in channels 31a, this provides a difierent. controlling force han. if he. ballsv be reversed in position The invention therefore. contemplates, the use of various numbers ofballs in, the channels. and, balls of diftierent weight disposed in any relationship. in theball trains.

The-hub construction I l, l2, M, l 9.,,etc,.is, also an important feature of the invention, It. will be app rent thatthe. tension on the runs of the belt. tends. to wedge flanges l3, [8r apart, this force being effective ata point and. in a. direction inditacting members movable. within thev channels.

2. A pulley in. accordance with claim 1 wherein the contacting members are composed of spherical balls, adapted to. move in series in the channels, in a. manner such that each ball contacts an adjacent ball to form a chain through cated byarrow 41, Figure. 5. Thisforce, of. course,

'flange l8 will constantly wobbleon such. connecwhich force may be exerted, the end ball in the parallel extending channel applying a controlling force substantially equal to the centrifugal force. of. a ball or balls disposed in the. outwardly extending channel.

3. A pulley in accordance with claim 2 wherein the controlling force is applied to a pin disposed in the parallel extending channel, the pin being of substantially the same diameter as the ball that it abuts and connected to one of the aligned members for conjoint movement therewith.

4. A variable ratio, pulley, comprising, a pair of axially aligned members having juxtaposed faces, of a shape to, en age the, sides of a V-belt therebetween, the width of the. faces in a radial direction being substantially in excess of the thickness of the belt, means, connecting the members together ina manner such that they rotate in unison. but are relatively movable axially, resilient means urging the members toward each other, means rotatable, with the pulley responsive to. oentriiugal force. for applying an opposing force to a. portion of the urge of the resilient means, the last named means comprising. guide means extending outwardly from the axis of rotation and joined at, the outer end thereof to second guide means extending in a direction angularly related to the direction of the first guide means, a mass oifixed. weight movable along both guide means forming a chain through which force may be, exerted, the. outer end of the chain being adapted to apply said opposing force, the

angular relationship of the two guide means being such that the opposing force is substantial- 1y equal to the centrifugal force exerted by only that portion of the mass disposed along the first named guide means when the member is rotating with portions of the mass disposed along both guide means.

CHARLES HUGH MINER.

REFERENCES CITED The following references are of record in the file of thispatent:

Number Number France Sept. 23, 1943 

